Since this is a concern mentions our Roku update, moving this to the update thread.
As for how to address it, may be a good idea to clear the one of the Rokus’ caches: Tablo TV App Cache - How and When to Clear It – Tablo . If that works, clear the others as well.
My Tablo prompted me to update my firmware to 2.2.54 today. I changed the audio setting and OTA streaming is working now!!! THANK YOU1
You could use a non-Roku playback device (like a Firestick), a slightly newer TV (that supports Dolby Digital—lots of old TVs support DD) or play them on an IPad etc. This is a case where the TV audio standards change over time and some older devices don’t support things seamlessly. Hope this helps.